Nasogastric and nasoenteric feeding tubes play a crucial role in treating patients having a compromised oral intake. Placement of these feeding tubes is routinely performed in a number of clinical settings throughout the United States including emergency rooms, hospital wards and intensive care units totaling greater than 1.2 million tubes annually. The most common method of feeding tube placement currently is blind placement, which is estimated to comprise 70 percent of feeding tube placements. Blind placement is performed at the bedside by nurses or other hospital staff, and entails blindly inserting the feeding tube down the nose, through the esophagus and into the stomach or small intestine.
Because the nurse or other hospital staff cannot see the distal end of the feeding tube during advancement, the feeding tube can be incorrectly positioned during the process. In extreme cases, the distal end of the feeding tube may pass into the cranium and into the patient's brain, while the nurse or other practitioner continues advancing the feeding tube believing that it is properly entering the gastrointestinal tract.
More commonly, misplacement of the feeding tube results in other serious complications including lung placement or puncture or esophageal puncture. It is estimated that 3.2 percent of all blind nasoenteric feeding tube placements result in the feeding tube being disposed in the lung. In approximately 1.2 percent of placements, the patient will suffer a punctured lung. In 0.5 percent of cases, the patient will die as a result of the procedure. It is estimated that in intensive care units alone, up to six thousand patients die each year from improperly placed feeding tubes.
Additionally, providing any feeding solution through the feeding tube into the lungs results in pneumonia with increased morbidity and mortality. Thus, it is critical to ensure that there has been proper placement of the feeding tube. Unfortunately, many common methods for during so leave patients at substantial risk.
Proper placement of the tube is verified using a variety of tests, including chest x-ray, pH tests, auscultation, or fluoroscopy. However, these tests only attempt to confirm position after placement when complications may have already occurred. For example, if fluoroscopy or X-ray confirms that the feeding tube is actually disposed in the lung, it does so only after the possibility of lung puncture or other damage to the lung tissue. Additionally, while X-ray imaging and fluoroscopy are often used, both only provide a two dimensional indication of location, i.e. placement below the diaphragm. In multiple instances, confirmation of placement has been given when the feeding tube had actually passed through the lung and along the diaphragm, rather than being disposed in the gastrointestinal tract. Moreover, X-ray or fluoroscopic confirmation does not clearly confirm placement in the small bowel rather than the stomach. Small bowel placement is generally preferred to prevent the risk of aspirating feeding solution.
Additionally, some of these techniques have additional limitations and drawbacks. For example, fluoroscopic exams and X-Ray verification can cost $400 or more and can expose the patient and the practitioner to harmful radiation. If a patient is pregnant, or a child, exposure to such radiation is highly undesirable. Additionally, the use of such verification procedures significantly prolongs the period of time that a patient must wait after a feeding tube is placed before feeding can begin. Because of this, the average time from ordering feeding tube placement to confirmation of placement and beginning of feeding is 22-26 hours. If the tube is placed improperly, the wait to begin feeding can take even longer as the process must be repeated. During this time, the patient is unable to obtain nourishment and any medications which may be delivered via a feeding tube.
Another complication which is common with patients receiving a patient tube is that the patients are often not coherent. The patient may be partially sedated or may be delirious. Thus, it is not uncommon for a patient to pull out a feeding tube which has previously been placed. This requires repetition of the procedure, again subjecting the patients to the risks set forth above. Thus, a simpler, safer method for placing feeding tubes would be highly desirable.
An alternate method for placement and verification of a feeding tubes is by use of an endoscope. Typically an endoscope is inserted into the mouth of the patient and advanced down until the endoscope has passed through the esophagus and at least into the stomach, and preferably through the pyloric sphincter and into the duodenum. In some applications, a guidewire is advanced to the proper location and the endoscope is removed. The guidewire is then manipulated to move it from the oral placement to a nasal placement, and a feeding tube is advanced along the guidewire into the desired location.
In other applications, the feeding tube is carried in a working channel (or along the side) of the endoscope. The feeding tube is sufficiently long that once the feeding tube has been placed, the endoscope can be removed over the feeding tube. The feeding tube is then cut and an appropriate adapter attached for feeding.
While placement and verification using an endoscope is advantageous, it also has several drawbacks. First using an endoscope usually takes considerable skill and is typically performed by physicians, often requiring a wait until a properly trained physician is available to place the feeding tube. Second, because the endoscope is typically placed through the mouth, an additional procedure must be used if the feeding tube is to be used nasoenterically. This involves advancing a structure through the nose and out the mouth, securing the end of the feeding tube (or a guidewire) to the structure, and then pulling the structure and the end of the feeding tube through the nose. Third, the use of an endoscopic procedure requires re-sterilization of the endoscope after each use. Lastly the procedure usually requires conscious sedation which increases the risk and cost of the procedure.
Each of the above-referenced methods for placing a feeding tube also has the problem of subsequently confirming proper placement of the feeding tube. As a patient moves, the distal end of the feeding tube can work its way out of the intestine and coil in the stomach. Depending on the particular concerns regarding the patient, it may be necessary to periodically confirm that the feeding tube is placed properly. This can require additional x-ray, pH tests, auscultation, or fluoroscopy, or the use of another endoscope to ensure that the feeding tube is properly placed. Each of these methods for confirming placement has the drawbacks mentioned above.
Accordingly, it would be desirable to provide a feeding tube which can be placed more conveniently and which can be used to confirm placement without the need for radiation or other traditional confirmation methods. Additionally, it would be advantageous if such a feeding tube and method of use could be accomplished by nurses and other medical staff.
In addition to nasogastric and nasoenteric feeding tubes, an improved jejunual extension tube in percutaneous gastrojejunal feeding tubes (PEGJ) that utilized direct visualization for advancement, placement and confirmation would be useful. Presently for PEGJ tubes the jejunal extension tube must be threaded through the existing gastrostomy tube or stoma into the small bowel. This is done using fluoroscopy or endoscopy to advance a wire into the small intestine and then a jejunal feeding tube is passed over the wire into the small intestine (jejunum). A jejunal extension tube with direct visualization and/or steering mechanism could perform the same task without the drawbacks of using endoscopy or fluoroscopy as noted previously.
In addition to improved feeding tubes, there are other situations in which prolonged visualization and access for irrigation/infusion and drainage would be beneficial. For example, in pancreatobiliary infections, it is not uncommon for the common bile duct (or associated duct) to become blocked and restrict flow of fluid into the duodenum. An endoscope or other catheter based method is typically used to place a shunt or stent in the pancreatic duct or the common bile duct to allow proper drainage of pus from the pancreatobiliary ducts through the common bile duct into the duodenum. Once the situation has been alleviated, an endoscope or other device may be advanced back into the duodenum to remove the shunt or stent. Of course, it is often difficult to tell if the situation has been fully alleviated, if the device has become misplaced, or if the symptoms have simply been reduced.
In these procedures, as well as others in the body, it may be advantageous to provide continued viewing capacity both to ensure proper placement of the structure used for drainage, and to allow medical personnel to get a view of the affected area to determine whether and how quickly healing and/or drainage is taking place. In these clinical situations such a device can replace or assist fluoroscopy and/or endoscopy for guidance, placement, confirmation and re-confirmation. In addition, such an indwelling device can be used to drain pus or other bodily fluids from body cavities as well as provide a conduit for irrigation and infusion of medications including antibiotics.